Keyboard



FIG. 1 is a top plan view of a keyboard showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof on an enlarged scale;

FIG. 5 is a left side view thereof on an enlarged scale;

FIG. 6 is a perspective view thereof. 

The ornamental design for a keyboard, substantially as shown and described. 